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1. Capacitance Increasing Technology (Patent Publication: US 6,310,762 and US 2002039275) |
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A novel active material, nonporous carbon, has been developed for a electric double-layer capacitor having characteristics entirely different from prior art activated carbons. The capacitor provides large electrostatic capacitance by a mechanism entirely different from that of an electric double-layer capacitor using activated carbons. The novel capacitor has improved performances including capacitance. Its electrodes are made of the carbon having crystallites of graphite-like carbon. When a voltage is applied, electrolyte ions intercalate between the layers of the crystallites of the carbon. Thus, electric double layers are newly formed. The intercalation is induced by the first cycle of charging, and the capacitance is maintained in the second and following cycles.
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TEM photograph of activated carbon |
TEM photograph of Nanogate Carbon® |
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The essential material of Premlis® is Nanogate Carbon® (NGC), a cathode active material.
The above TEM photographs clearly show that the activated carbon (left) has innumerable pores several nanometers in size while NGC is made up of compact turbostratic structures. Average interlayer spacing can be measured by the X-ray diffraction method. This structural construction provides high electrostatic capacitance characteristics.
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2. Rated Voltage Increasing Technology (Patent Publication: US 7,141,230) |
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Stored energy in a capacitor is proportional to the square of voltage, so the increase of the rated voltage significantly contributes to the increase of the stored energy in the capacitor. Presently the voltage of conventional activated-carbon type capacitors is very low, only 2.7 V or below.
We JEOL/ACT have developed new technology to dramatically enhance the voltage, where the based idea was to control electrochemical activities of the carbon surface in the electrolyte.
This is also one of key technologies in our new carbon, the Nanogate Carbon®.
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3. Carbon Evaluation Technology (Patent Publication: JP 2000340469)
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It is very important that a material having high performance is actually available for industrial applications.
Advanced Capacitor Technologies Inc. (ACT) has practically used so many analytical instruments, most of which are JEOL's own products. Thereby, we could also develop evaluation techniques for inspections of each receiving material.
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The right figure shows one of examples, so-called pulse-NMR instrument and its data.
Using the pulse-NMR, we can analyze chemical states of proton or hydrogen (-H) in the carbons. The chemical state directly correlates electrochemical activities or stability of the carbons mentioned above. |
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Electrode made of Nanogate Carbon®
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Nanogate Carbon powder is mixed with resin binder and processed into very thin electrode sheets.
Micro-morphology observation is very important as the basic criteria for controlling such properties as the sheet density, tensile strength, and specific resistance.
In the SEM photograph taken in the low-energy (300eV) electron beam condition, we can observe ultra-fine structures of the fibril binder.
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■ Naming of the Nanogate Capacitor
In October 2003, we made a technical presentation of our product called the Nanogate Capacitor and applied for trademark registration. However, since the name Nanogate was already approved as a trademark for Nanogate AG in Germany.
Accordingly, we shall not use the name Nanogate Capacitor from now on.
■We have taken over the rights to Nanogate Carbon®, a new electrode material developed by JEOL Ltd.
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